Method of treating paper



June 6, 1933. E, p m' JR I 1,913,017

METHOD OF TREATING PAPER Filed J1me 29, 1951 by. w

Patented June 6; 1933 UNITED STATES 'EDHUNDP. A BPIN, JR, IPOBT EDWARDS, WISCONSIN, ASSIGNOR TO NEIOOSA PATENT OFFICE.

EDWARDS YA PER COMPANY, 01' PORT EDWARDS, WISCONSIN, A CORPORATION O1 WISCONSIN mrrnon or rnmrme runs Application fl ed June 29, 1931. Serial No. 547,558.

This invention relates to a method for treating web material such as paper to increase'the strength of the web.

- preparing impregnated creped paper. I

- roll 6 immersed .into the sizing solution in.

It is a further object of this invention to prepare a creped sheet material which holds its shape and is not readily decrinkled. f

Other andiurther'objects of this inven-' tion will be apparent from the following description and ap ended claims. v

This invention in a preferred form) is illustrated in the accompanying drawing and hereinafter more fully described.

On thedrawing: v

Figure 1 is a side elevational view of the left 'hand end of the apparatus ulsedj in carrying out the process of this invention.

Figure 2 is a side elevaticnal view of the righthand end of the. apparatus as shown in Fi are 1.

As shown on the drawing: v The reference numeral 1 indicates a web from a roll 2 which is passed over rollers 3 into a tub 4 containing a sizing composition. Theweb material 1 after passing over the guide rolls 3 is directed under a octor the" tank 4;. The webwl' is then passed-between rolls. 5 'and' 6 to spread the sizing material uniformly over the sheet. The web isthe'n directed back; again into the sizing bath inthe tub 4 bypassing-it around a roll 7. The rolls 5, 6, arid 7 may'be supported in any suitable manner suchas for example by mounting them in a frame; The support has not been-illustrated in the drawing and, the rolls are shown diagrammatically for clearness. b ,v p Thesweb is-passed through a second pair 5'0 of rolls- 9 and 10 wherein the excess sizing varied accordin vals' along its lower peripher met the current of heated air rom the heatmaterial is removed. It should be understood that the number of press rolls may be to the. particular need in carrylng out t e process. Two sets are shown in the drawing but in some cases one set of press rolls is suflicient whereas in other instances it is found desirable to insert three or even more pairs of rolls. 1

The sized sheet is in a moist or damp condition from the passage through the sizing bath and has a tendency to adhere to roll 9. A creping attachment consisting of a stub blade 11 and a small auxiliary roll 12 are suitably mounted to press against the roll 9. The roll 12 is mounted a short distance above the blade 11 so as to press against the web immediately preceding its contact with the blade 11. The moistened. sheet on. the roll 9 prior to its contact against the stub blade 11 adheres to the roll 9 and upon reaching the blade 11 is scrapedtherefrom. I

thus causing the paper to become crinkled or creped. The tenacity with which the moistened sized sheet adheres to the roll 9 gi'egtly aids the creping action of the scraper The now creped web 1 is passed onto a: wire or endless conveyor belt 13. The wire'i or conveyor belt 13 is directed around rollers 14 and 15 which are driven by any suit able means such as for example by a belt drive from a main driving roll 16.

A spraying device 17 is positioned after the creping attachment so as to direct a spray upon the creped sheet as it moves a ong the conveyor belt 13. The spraying device 17 may be of any suitable make but I prefer to use a device similar to that described in mv copending application Serial No. 135,729,1ild September 16th, 1926.

A heater 18. is suitably supported as by a frame 18" positioned a short'dlstance beyond the conveyor belt supporting roll 14. An

air duct '19 issultably connected to the heater 18- and extends therefrom over the travcling web 1. The air duct 19 is provided with a number of baflles 20 spaced at interso as todier 18 whichis provided with a blowing deweb 1 under a second set of heaters.

"14 and 23.

A second heating unit comprising a pair of heaters 28 and 29 mounted on supports and 26 is provided for heating the partially dried web from the lower conveyor belt 13. The heater units 28 and 29 may be any one of the numerous tvpes of commercial'air heaters on the market and may be heated by any suitable ,means. A large elongated duct 30 tapered so that its greatest cross sections are at the ends thereof and its smallest cross section is at the middle extends from heater 28- to heater 29. The air duct 30 is provided with a number of bafiies 31 and 32 which are placed at spaced intervals along its lower periphery. The bafiles extend upwardly a short distance into the interior of the duct 30. Baf- .fles 31 are inclined toward the heater 28 while. bafiles 32 are inclined toward the heater 29 to effect a uniform distribution of heated air throughout the entire length of the duct'30. The tapered duct 30 having itssmallest cross section at the middle further aids in the uniform distribution of heated air throughout the entirelength.

A winder roll 33 suitably supported as by the frame 34 is positioned a short distance beyond the heater 29 to receive the treated web 1. The winder roll 33 may be hand operated by means of a crank 35 or any suitable driving means may be used for regizoving the treated web from the conveyor To recapitulate briefly the operation of the device in which my process may be effected, a web such as a paper sheet 1 is unrolled from a roll 2 and passed through a size tub 4 which is steam jacketed and may be heated wherein the web is thoroughly imv pregnated with the sizing material. Upon leaving the size tub the paper web is passed between pressrolls 9 and 10 to remove the excess size. The web is scraped from the press roll 9 to form a creped sheet which is allowed to drop on a traveling conveyor wire 13. If desired, the creping operation may be dispensed with and the uncreped sheet fed to the conveyor wire 13. The sheet passes under a spray device 17 while on the conveyor wire and is sprayed with a hardening solutionto set the still wet size on the sheet. All ad;

' the spray the sheet is passed beneath a dryer 19 wherein it is partially dried. It is then next elevated to a conveyor wire 22 where it passes beneath an elongated air duct 30' under which the drying process is finished. The thoroughly dried web is then removed from the conveyor wire 22 at 24 and wound into a roll 33. 4

While any sizing material may beused in the size bath I prefer to use a solution such as described in my copending Serial No. 563,667, filed September 18, 1931 and having essentially the following composition:

Glue or gelatine 40 to 99% (dry weight) Glycerine, or other polyhydric alcohol 0 to 30% Liquid rubber latex 1 to 40% Triethanolamine or similar substance 0to30% It will be seen from the above range of proportions used in the preferred sizing solution that the materials may be varied throughout a wide range. However, in most cases, 'it is essential that the glue or gelatine content should not be allowed to drop below in order to assure a glazed finish on the paper.

While any hardening solution may be used in the spray treatment I prefer to subject the creped sheets to a spray consisting of a mixture of furfural and formaldehyde. The furfural and formaldehyde may be mixed and sprayed directly on the material or the mixture of furfural and formaldehyde may be diluted by the addition of commercial denatured alcohol and/or distilled water. The spray treatment as pointed out sets the sizing material already impregnated into the web and results in a waterproof coating upon the web. The resulting effect is somewhat similar to that obtained by tanning leatheia Either furfural or formaldehyde may beusedalone in the spray hardening treatment but I prefer to use a composition consisting of a mixture of 75% furfural and 25% formaldehyde. However other aliphatic aldehydes and ketones may be substituted for the formaldehyde and furfural.

" The resulting treated paper'has a I greatly increased mullen and tensile strengt over ing t hyde and 75% furfural.

that of ordinary paper. The paper sheet also has a great resistance to tearing action and a high resistance to penetration of water, oil or similar liquids. The paper has a pliability which will not be lost upon ageing.

It has been found furthermore that paper treated by my process has very good peeling properties from materials of an adhesive nature. This quality makes the treated paper highly desirable for use in making paper backed adhesive tape.

Many changes may be made in the details and arrangement of the apparatus and the steps of the process and I do not wish to be limited otherwise than as necessitated by the prior art and scope of the appended claims.

I claim as my mvention:

'1. The process of treating paper which comprises passing a web of paper through a bath containing a gelatinous material, a pollyihydrio alcohol and rubber latex and spraying the web as it emerges from the bath with a solution containing an aldehyde to form a hardened surface on the web.

2. The method of treating web material which comprises passing the said web ma-- terial through a bath containing a gelatinous material and a polyhydric alcohol, subsequently passing the web through press rolls, crepin the web by scraping it from the press rol s, and spraying the creped web with a fluid which reacts with the gelatinous material to set the creped web.v

3. The process of treating paper which comprises passing a websof paper through a bath containing a gelatinous material, a polyhiydric alcohol and rubber latex, crepe web as it emerges from the bath and coacting the material impregnated on the web with an aldehyde to form a hardened surface on the web.

4. The process of treating paper which comprises passing a paper web through a bath having the following composition:

Glue or gelatine 40 to 90% Glycerine 0 to Liquid rubber latex 1 to Triethanolamine 0 to 30% ereping the impregnated sheet as it emerges from the bath and spraying the creped sheet with a solution containing 25% formalde- In testimony whereof Ihave hereunto subscribed my name at Port Edwards, Wood County, Wisconsin. 1 I

EDMUND P. ABPIN,'JB. 

